Slack adjuster



J. W. CLARK SLACK ADJUSTER Oct. 24, 1939.

Origin'al' Filed Dec. 21, 1936 2 Sheets-Sheet l I M M LI.

Patented Oct. 24, 1939 PATENT OFFICE SLACK ADJUSTER James W. Clark, Monmouth, Ill.

Continuation of application Serial No. 117,081, December 21, 1936. This application May 13, 1938, Serial No. 207,858. In Canada January 22 Claims.

This invention relates to slack adjusters for use with air brake equipment for railway cars.

locomotives, tenders, urban and interurban cars and the like.

It is primarily an object of the invention to provide a slack adjuster which is operable through the instrumentality of the mechanism substantially as hereinafter described, which mechanism becomes active upon abnormal travel of the piston comprised in said equipment.

An important object of the invention is to maintain substantially uniform the travel of the aforesaid piston.

Another important object of the invention is to provide means operating under the influence of the push rod connected to said piston to take up automatically any slack which may occur as a result of wear upon the brake shoes or from any other cause which would effect the desired uniform piston travel.

A further important object of the invention is to effect a resistance to the undesired action of the slack adjuster, which resistance is brought about by causing the said adjuster to operate si- 36 multaneously with the brake application.

The invention consists in the details of construction and in the, combination'and arrangement of the several parts of my improved slack adjuster whereby other objects and important ad- 30 vantages are attained and the device rendered simpler, less expensive. and otherwise more convenient and advantageous for use as will be hereinafter set forth, or will be apparent during the course of the following description.

The present application is a continuation of my application for Slack adjusters, Serial Number 117,081, filed December 21, 1936; and which last named application is a continuation of my application for Slack adjusters, Serial Number 295,555, filed July 26, 1928.

In order that my invention may be better understood, I will now proceed to describe the. same with respect to the accompanying drawings, wherein:

Figure 1 is a diagrammatic view illustrating a slack adjuster constructed in accordance with an embodiment of my invention;

Figure 2 is an enlarged detailed fragmentary view partly in section and partly in elevation illustrating the mounting of the capstan and certain of the parts associated therewith;

Figure 3 is a vertical sectional view taken lengthwise of the frame illustrated in Figure 2 with certain of the parts in elevation;

Figure 4 is a diagrammatic view illustrating a further embodiment of my invention.

My improved slack adjuster may be employed in connection with the regular brake equipment without any material change in the arrangement of the brake rigging.

The operating mechanism comprises a capstan embodied with a rack and pinion and the necessary operating appliances for both of the purposes of receiving the operative movements 3 from the push rod and transmitting such movements to the brake rigging. A detailed description of the mechanism and its accompanying appliances is hereby given as follows:

As particularly illustrated in Figure 1, C denotes a brake cylinder in which operates a well known type of piston carrying the push rod I. The rod I is operatively connected through the medium of a pin 2 with the live cylinder lever 4 which constitute parts of all air brake equipment.

The pin 2 also provides an operative connection between the rod l and an end portion of the operating lever 3 comprised in my improved slack adjuster. The rectilinear movement of the push rod l imparts swinging movement to the lever 3 as well as the live cylinder lever 4 and for which reason said lever 3 is provided with a slot 5 through which the pin 2 is disposed in order to provide for such swinging movement. The slot 5 permits the lever 3 to move lengthwise at its connection afforded by the pin 2 allowing for a greater distance from the pin of the push rod to the center of the capstan or rotatable member A. The lever 3 has pivotal connection with the upper portion of a pin 6.

This pin 6 is supported by a capstan frame F which is bolted or otherwise aifixed to a bracket B which in turn is bolted or otherwise eifectively secured to the car sills. Rotatably mounted upon the pin 6 is a capstan or rotatable member A provided with the upper and lower flanges 9 and Ill. The peripheral portion of the upper flange 9 is provided therearound with a series of ratchet teeth H herein disclosed as fifteen in number. These teeth are of duplicate form. Each of the teeth II is placed in relation to the ratchet teeth I2 provided in the peripheral portion of the lower flange l0 and equidistantly spaced therearound. As herein disclosed, the teeth i 2 are ninety in number and of similar or duplicate form. Each of the teeth I! is placed in vertical alignment with a point midway between two of the adjacent teeth l2, or each of the teeth H may be placed in vertical alignment with one of the teeth The lever 3 has pivotally connected therewith, as at M, a dog, or pawl l5, which is constantly urged into contact with a tooth H through the medium of the spring l6 carried, as at H, by the lever 3. Pivotally mounted, as at I8, with the capstan frame F is a second pawl l9 constantly urged into contact with the teeth l2 through the medium of the spring 20 also carried by the capstan frame F.

The peripheral portion of the capstan or rotatable member A between the flanges 9 and I0 is provided therearound with the teeth 2| which mesh with the teeth 22 provided in'a marginal portion of a rack bar 23. The teeth 2i and 22 are maintained in mesh through the instrumentality of the roller 24 contacting with the edge or face of the bar 23 opposite to the teeth 22, as particularly illustrated in Figure 2 of the accompanying drawings.

This roller 24 is rotatably mounted upon a pin 25 carried by and bridging the space between the outer end portions of the arms 26; said arms having their inner portions connected with the pin 6, one arm being thus connected below the capstan A, the other arm above the adjacent end portion of the lever 3. The outer extremity of each of the arms 26 has aflixed thereto an end portion of a brace arm 2?, the opposite end portion of which arm 2'! being bolted to the capstan frame F. The engagement between the bar 23 and the capstan A is such that upon rotation of the capstan A as a result of undue outward travel of the rod I push is imposed upon the rack bar 23.

The rack bar 23 is operativelyconnected, as at 23, between the levers 29, said levers at all times being in parallelism one above the other. One of these levers 29 being disposed above and the other below the guide member 30. The guide 38 comprises an elongatedmember disposed on the center line of the cylinder C. Said guide consists of two bars, one above the other, between which the adjacent end portion of the dead cylinder lever 31 has movement. As disclosed in the aforesaid Figure 1, one end portion of the guide 39 is supported by the cylinder C while the opposite end portion may be supported by a car sill and thus act as a brace for the cylinder C.

At a predetermined point midway their ends the levers 29 have disposed therethrough a pin 3| which is also disposed through a slot 32 provided in the guide 30 and extending lengthwise thereof. The extremities of thelevers 2!! remote from the rack bar 23 are pivotally connected, as at 33, with the bars 34 which in turn are pivotally connected, as at 35, to a suitably supported cross piece 36. V t

The pin 3] also has operatively connected therewith an end portion of the dead cylinder lever 3'7, the slot 32 permitting the adjacent end portion of the lever 31 to be adjusted in a direction lengthwise thereof and at the same time holding said lever 31 against movement in a direction lengthwise of itself. The lever 31 is operatively connected with the live cylinder lever A at points midway the ends thereof by the tie rod 38.

As the rod l moves outwardly swinging movement is imparted to the lever 3; and in the event that the outward movement of the rod l or piston travel is for a. distance greater than that for which the capstan A is set without operating, the pawl l5 will engage the first tooth ll on flange 9, and in the course of its movement will cause the capstan or rotatable member A to be rotated a distance sufficient to permit the pawl H) to engage the next tooth IE on the holding tance suflicient to bring the pawl i9 into engagement with three of the teeth l2 on the holding or lower flange l0 within the space separating the perpendicular alignments of the teeth ll on the operating or upper flange 9 between which the pawl [9 was brought into action in making the operation above described. The capstan A is held against retrograde movement by the pawl I!) which as particularly illustrated in Figure 2, has its working end engaged with three of the teeth l2. During this rotation of the capstan A just referred to, push will be imposed upon the bar 23 resulting in a shifting of the pin 35 in the slot 32 and which adjustment in proper ratio will be transmitted to the levers 3! and 5. By this action slack is taken out of the brake rigging and the desired uniform travel of the brake piston or rod I will be maintained; and the maintaining of an uniform piston travel will regulate and maintain substantially constant the amount of slack within the brake rigging.

Under normal conditions, or when the brake piston has the desired travel or less, it is to be understood that the swinging movement of the operating lever 3 will have no effect upon the movement of the capstan A as the pawl l5 only moves forward and backward in the space seprating the two teeth H on the flange 9 between which it is moving; but upon further wear of the I of which is either in perpendicular alignment or adjacent toa point that is in perpendicular alignment with the last succeeding tooth l of the alignments hereinbefore referred to on the operating flange 9, then the slack adjuster upon additional wear of the parts hereinbefore named will again operate as previously described and each succeeding operation takes place in like manner.

It is to be particularly noted that the teeth I 2 on the holding flange in are small and arranged in succession one immediately adjacent to the other. Thus providing means to take up effectively slack in small amounts at a time as it develops by wear of the brake shoes and rigging. Also, it is to be noted that the pawl IS, in its co-operation with the teeth l2, successively engages several of said teeth l2 between the actions of the pawl l5 engaging two adatively connected, as at 39, with an end portion of the lever 49. Operatively connected with the lever 49 at a desired point intermediate its ends is a rod 4| which in turn is operatively connected with a dead lever 42. The end portion of the lever 4llremote from the bar 23 is, at 50, operatively connected through the medium of a bar 43 with a second lever 44, herein disclosed as in converging relation with respect to the lever 40. The lever 44 has its end portion remote from the bar 43 operatively connected with a rod 45. The rod 45 is operatively connected with a bracket 46 adapted to be secured to a car sill. The lever 44 is operatively connected through the medium of a rod 41 with the lever 4'. It is to be noted that the rods 41 and 4'! together form one rod of the original brake rigging, which rod has been cut in the manner disclosed in Fig. 4, and the levers 40 and 44 interposed between the ends thereof.

Upon rotation of the capstan A pull imposed upon the bar 23 results in pull being imposed upon the rods 4| and 41 one toward the other and by such action slack is taken out of the brake rigging and a substantially uniform brake piston travel is maintained. Connected with the lever 40 and with a suitably positioned bracket 40 is a retractile spring 48 of requisite tension to keep the levers 40 and 44 in their proper places and to overcome the inertia of said levers while the brakes are being released. Supporting the opposite end portions of the levers 4!] and 44 are the lever carries 49 of a conventional type. The effects of the hookup, or embodiment, shown in Figure 4 tends to adjust the slack in the brake rigging and to maintain a uniform brake piston travel the same as hereinbefore set forth in connection with the embodiment of my invention as particularly described with reference to Figure 1.

Hereinbefore the direct and simultaneous operation of the slack adjuster with the brake application has been described; but by turning the capstan upside down, changing the rack bar so that the same comes into contact with the opposite side of the pinion from which side said bar is shown as contacting in the accompanying drawings, and changing the positions of the pawls so that they engage their respective teeth in proper manner, the slack adjuster can be caused to operate while the brakes are being released. Herein arises the question of what is known as undesired action, that is the operation of the slack adjuster upon the weakening of the resistance to the brake application, caused by slight and momentary tilting of the truck levers due to track conditions, the movement of the trucks and certain parts of the running gear. This condition exists upon freight cars to a greater extent than upon passenger cars, due to the more loose construction of the former. Yet frequently the last named cars obtain too short a piston travel due to the aforesaid undesired action of an automatic slack adjuster resulting in damage therefrom.

The direct and simultaneous operation of the slack adjuster with the brake application as fully described hereinbefore and as disclosed in the accompanying drawings acts as a causative agent to prevent the above described undesired action. Or in other words the simultaneous operation of the slack adjuster with the brake application effects or opposes a resistance to undesired action. It is seen that when the brakes are applied the piston moves forward, and if the pistons movement is unduly as described hereinbefore the pawl l5 comes into contact with a tooth H, and no slight and momentary tilting of the truck levers, nor movement of parts of the running gear and trucks, would cause the aforesaid undesired action of the slack adjuster. This fact becomes apparent when it is understood that during such operation of both the brakes and slack adjuster simultaneously that the inertia of both the brake rigging and the slack adjuster must be overcome together, and the adjustment of parts of the rigging is to be accomplished, and the travel of the brake piston is to be shortened synchronously with said simultaneous operations. With such a method of operation as immediately before described the slack adjuster will not operate until a positively slightly longer piston travel is obtained. It is submitted that the slack adjusting mechanism hereinbefore described, particularly the structure of the holding flange possessing teeth entirely around said flange, disclosed as being relatively small with respect to the operating teeth, and arranged in succession one immediately adjacent to the other, is well adapted for the successful and practical operation of the slack adjuster simultaneously with the brake application.

Whereas if the operation of the slack adjuster were changed so that it operated as the brakes are being released, which method of operation is universally accepted as being the best, the causes being absent which prevented the aforesaid undesired action in the first explained method of operation, each slight tilting of the truck levers, or movement of the trucks or parts of the running gear toward the center of the car would cause the piston to move forward unduly, carrying with it the push rod, the operating arm, with the pawl thereon. These movements would permit said pawl to become engaged with the operating teeth so frequently that too short a piston travel would result therefrom, resulting in the brake shoes not being removed from the wheels upon release of the brakes, giving too strong a braking power, and thereby causing slid fiat wheels and broken equipment.

It is to be understood that the capstan A is to be set with respect to the center of travel of the pin 2 in accordance with the required uniform travel of the brake piston. Freight cars generally are supposed to have an eight inch running piston travel, passenger cars seven inch running travel, tenders six inch running travel, and locomotives four inch running travel. To compute the correct distance for the required piston travel, an isosceles triangle is constructed the vertex of which is the center of pin 6, and the side lines are drawn through two adjacent teeth H on the operating flange 9. Add to the above triangle a triangle formed by drawing a line from the center of pin 6 through a point on the periphery of the holding flange H] in perpendicular alignment with a tooth H on the operating flange 9. The other side of this last named triangle is a line drawn from the center of pin 6 through the next tooth #2 on the holding flange IEI. Bisect the sum of these triangles; find the point at which the outer sides of the triangle, formed by the sum of the above specified angles, are'eight inches apart on a line perpendicular to the line which bisects the sum of the said angles. The distance from the center of pin 6 to the point where the line drawn between the outer sides of the sum of the above specified angles intersects the line which bisects the sum of the two angles is the correct distance to set the center of capstan A from the center of travel of the pin 2 for an eight inch piston travel. In like manner the correct setting of the capstan for seven, six, and four inch travels can be computed.

No definite diameter is required for the flanges 9 and I0, altho in practice from eight to twelve inches appear to be convenient sizes. The aforesaid flanges 8 and It! may be transposed to suit the convenience of installation. And it is, also, to be understood that the number of teeth I I and of teeth 52 may be varied.

From the foregoing description it is thought to be obvious that a slack adjuster constructed in accordance with my invention is particularly well adapted for use by reason of the convenience and facility with which it may be manufactured, assembled, installed, and operated manually when such operation is required. Also, it is obvious that my invention is susceptible to changes and modifications in both structure and operation, such as effecting the operation of the same upon release of the brakes, without departing from'the principles and spirit thereof and for these reasons I do not wish to be understood as limiting myself to the precise arrangements and formations of the several parts herein shown and described in carrying out my invention in practice except as hereinafter claimed.

I claim:

1. In an air brake equipment; the combination with a push rod and a live cylinder'lever operatively connected therewith; a rotating mechanism; an operating arm connecting the said push rod with the mechanism; means carried by said arm to rotate the mechanism in one direction; means for preventing the retrograde movement of said mechanism; a second lever operatively connected with said mechanism through the medium of a movable rack bar; said mechanism being provided with teeth with which said rack bar is held in mesh; means for holding the second lever for swinging movement; the aforementioned operating arm, rotating mechanism, first named means, and rack bar being adapted for imposing movement upon said second lever upon abnormal travel of said push rod; a third lever supported at one end portion for swinging movement; means for operatively connecting the opposite end portion of the third lever to the second lever; an operative connection between the third lever and the live cylinder lever; a dead lever; an operative connection between the dead lever and the second lever; said movement imposed upon the second lever upon abnormal travel of the push rod efiecting movement of the third lever, the dead lever, and the live cylinder lever to take up slack in the brake rigging.

2. In an air brake equipment; the combination with a push rod and a live cylinder lever operatively connected therewith; a rotating mechanism; an operating arm connecting the said push rod with the aforesaid mechanism; means carried by the said arm to rotate the mechanism in one direction; means for preventing the retrograde movement of said mechanism; a second lever operatively connected with said rotating mechanism through the medium of a movable rack bar; said mechanism being provided with teeth with which said rack bar is held in mesh; means for holding the second lever for swinging movement; the aforementioned operating arm, rotating mechanism, first named means, and the rack bar being adapted for imposing movement upon said second lever upon abnormal movement of the push rod; a third lever supported at one end portion for swinging movement; means for operatively connecting the opposite end portion of the third lever to the second lever; an opera: tive connection between the thirdlever and the live cylinder lever; a dead lever; an operative connection between the dead lever and the second lever; said movement imposed upon the second lever upon abnormal travel of the push rod effecting movement of the third lever, the dead lever, and the live cylinder lever to take up slack in the brake rigging; and means co -acting with the second lever to maintain the second and third levers in proper positions and to overcome the inertia of said levers while the brakes are being 7 released.

3. In an air brake equipment; the combination with a push rod and a live cylinder lever operatively connected therewith; a rotating mecha nism; an operating arm connecting the said push rod with the mechanism; means carried by said arm to rotate the said mechanism in one direction; means for preventing the retrograde movement of said mechanism; a second lever operatively connected with the aforesaid mechanism through the medium of a rack bar; means for holding said bar in mesh with teeth provided upon said mechanism; means for holding the second lever for swinging movement; the aforementioned operating -arm, rotating mechanism, first named means, and the'rack bar'being adapted for imposing movement-upon said second lever upon abnormal travel of the push rod; a third lever supported at one end portion for swinging movement; means for operatively connecting the opposite end portion of the third lever to the second lever; an operative connection between the third lever and the live cylinder lever; a dead lever; an operative connection between the dead lever and the second lever; said movement imposed upon the second lever upon abnormal travel of the push rod effecting movement of the third lever, the dead lever, and the live cylinder lever to take up slack in the brake rigging; and a spring connected to said second lever and of a tension to maintain the second and third levers in proper positions and to overcome the inertia of said levers while the brakes are being released.

4. In an air brake equipment; the combination with a push rod and a live cylinder lever operatively connected therewith; a rotating mechanism; an operating arm connecting the said push rod with the mechanism; means carried by said arm to rotate the mechanism in one direction; means for preventing the retrograde movement of said mechanism; a secondlever operatively connected to said mechanism through the medium of a rack bar; said mechanism being provided with teeth with which said bar is held in mesh; means for holding the second lever for swinging movement; the aforementioned operating arm, rotating mechanism, first named means, and the rack bar being adapted for imposing movement upon said second lever upon abnormal travel of the push rod; a third lever supported at one end portion for swinging movement; means for operatively connecting the opposite end portion of the third lever to the second lever; an operative connection between the third lever and the live cylinder lever; a dead lever; an operative connection between the dead lever and the second lever; said movement imposed upon the second lever upon abnormal travel of the push I lever; and the pivotal mounting for the saidsecond lever being at an end portion thereof when eiTecting movement of the said dead lever.

5. In an air brake equipment; the combination with a push rod and a live cylinder-lever operatively connected therewith; an operating mechanism; an operating arm connecting the said rod with the operating mechanism; means carried by the aforesaid arm to operate the said mechanism; means for preventing the retrograde movement of said mechanism; a second lever operatively connected with the aforesaid mechanism through the medium of a rack bar; said mechanism being provided with a pinion with which said bar is held in mesh; means for holding the second lever for swinging'movement; the aforesaid arm, operating mechanism, first named means, and said bar being adapted for imposing movement upon said second lever upon abnormal travel of the said rod; a third lever supported for swinging movement; an operative connection between the third lever and the second lever; an operative connection between the third lever and the live cylinder lever; a dead lever; an operative connection between the dead lever and the second lever; said movement imposed upon the second lever upon abnormal travel of the push rod effecting movement of the third lever, the dead lever, and the live cylinder lever to take up slack in'the brake rigging; the pivotal mounting for the third lever being at the end portion thereof remote from the operative connection between the second and third levers.

6. In an air brake equipment; the combination with a push rod and a live cylinder lever operatively connected therewith; an operating mechanism; an operating arm connecting the push rod with said mechanism; means carried by said arm to operate said mechanism; means for preventing the retrograde movement of said mechanism; a second lever operatively connected with said mechanism through the medium of a rack bar; said mechanism being provided with teeth between the end portions thereof; said raok bar being held in mesh with said teeth; means for holding the second lever for swinging movement; the aforesaid arm, operating mechanism, first named means, and said bar being adapted for imposing movement upon said second lever upon abnormal travel of the push rod; a third lever supported for swinging movement; means for operatively connecting the third lever to the second lever; an operative connection between the third lever and the live cylinder lever; a dead lever; an operative connection between the dead lever and the second lever; the aforesaid movement imposed upon the second lever upon abnormal travel of the push rod effecting movement of the third lever, the dead lever, and the live cylinder lever to take up slack in the brake rigging.

7. In an air brake equipment; the combination with a push rod and a live cylinder lever operatively connected therewith; an operating mechanism; means operating upon abnormal travel of the push rod to operate said mechanism; means for preventing the retrograde movement of said mechanism; a second lever operatively connected with said mechanism through the medium of a bar provided with an operative connection with said mechanism; means for holding the second lever for operative movement; the said second lever being adapted to operate as of both the first and the second class; the first namedmeans, the aforesaid mechanism, and the said bar being adapted for imposing movement upon the second lever; a thirdlever supported for operative movement; means for operatively connecting the third lever to the second lever; an operative connection between the third lever and the live cylinder lever; a member comprised in the brake rigging; an operative connection between said member and the second lever; aforesaid movement imposed upon the second lever effecting movement of the third lever, the live cylinder lever, and the aforesaid member comprised in the brake rigging to take up slack in said rigging.

8. In an air brake equipment; the combination with a push rod and a live cylinder lever operatively connected thereto; an operating mechanism; means operating upon abnormal travel of the push rod to operate said mechanism; said means including an operating arm; means for preventing the retrograde movement of said mechanism; a second lever operatively connected with said mechanism through the medium of a rack bar; said mechanism being provided with teeth with which said bar is held in mesh; means for holding the second lever for swinging movement; said second lever being adapted to operate as of both the first and the second class; the first named means, the aforesaid mechanism, and the rack bar being adapted for imposing movement upon the second lever; an operative connection between the second lever and the live cylinder lever; a member comprised in the brake rigging; an operative connection between said member and the second lever; the aforesaid movement imposed upon the second lever efiecting movement of the second lever, the live cylinder lever, and the aforesaid member comprised in the brake rigging to take up slack in said rigging.

9. In an air brake equipment; the combination with a push rod and a live cylinder lever operatively connected therewith; an operating mechanism; means operating upon abnormal travel of the push rod to operate said mechanism; means for preventing the retrograde movement of said mechanism; a second lever operatively connected with said mechanism through the medium of a rack bar; said mechanism being provided with teeth with which said bar is held in mesh; means for holding the second lever for swinging movement; said second lever being adapted to operate as of both the first and second class; the first named means, the aforesaid mechanism, and the rack bar be ing adapted for imposing movement upon the second lever; an operative connection between the second lever and the live cylinder lever; a member comprised in the brake rigging; an operative connection between said member and the second lever; the aforesaid movement imposed upon the second lever effecting movement of the second lever, the live cylinder lever, and the aforesaid member comprised in the brake rigging to take up slack in said rigging.

10. Incombination with a brake rigging including levers interposed in the central portion thereof and operatively connected therewith; an operative connection between said levers; one of the aforesaid levers being adapted to operate as of both the first and the second class; the other lever thereof being adapted to operate as of the second class; a push rod of a brake equipment; a mechanism; an operative connection between the mechanism and the said rod; said connection including a swinging arm; said mechanism being operatively connected with the aforesaid levers through the medium of a rack bar held in mesh with a pinion provided upon said mechanism; means operating upon abnormal travel of the push rod effecting the movement of said mechanism; said levers being adapted to transmit the movements of said mechanism whereby slack is taken out of said rigging with substantially equal effectiveness in both end portions thereof and a substantially uniform brake piston travel is maintained.

11. In combination with a push rod and a live cylinder lever operatively connected thereto; a second lever interposed in the central portion of a brake rigging; a mechanism operatively connected with said rod through the medium of a swinging arm and means carried thereon; an operative connection between said mechanism and the second lever; said connection comprising a rack bar meshing with teeth provided upon said mechanism; a member comprised in the brake rigging; an operativev connection between said member and the second lever; an operative connection between the second lever and the aforesaid live cylinder lever; the aforesaid means carried by said swinging arm operating said mechanism upon abnormal travel of the push rod; said second lever being adapted to operate as of both the first and the second class; thereby transmitting the operations of said mechanism through the aforesaid operative connections with substantially equal eifectiveness toboth the live cylinder lever and the said member comprised in the brake rigging.

12. The combination with a push rod, a live cylinder lever, a dead lever, and an operative connection between said levers as comprised in a brake equipment;- a rotating member; means operating upon abnormal travel of the push rod for operatively connecting said rod with the rotating member; said means including an operating arm swinging with respect to the axial center of the rotating member; means for holding the rotating member against retrograde movement; a transmission lever; a rack bar meshing with a pinion provided upon said member; said transmission lever being constructed and arranged whereby an end portion thereof being operatively connected to said bar, the opposite end portion thereof being pivoted within the brake rigging, and the central portion thereof being operatively connected to the said dead lever; the first named means, rotating member, and the rack bar being adapted to impose push upon the said transmission lever thereby effecting movement of the dead lever and the live cylinder lever to maintain a substantially uniform brake piston travel; and the said uniform brake piston travel regulating the slack within the brake rigging.

13. In combination with a push rod, a live cylinder lever, a dead lever, and an operative connection between said levers as comprised in a brake equipment; an operating mechanism; an operating lever; an end portion of said operating lever being operatively connected to said push rod, the other end portion thereof being operatively connected to said mechanism; means carried by said operating lever to operate the aforesaid mechanism upon undue travel of the push rod; means for holding the afore-named mechanism against retrograde movement; a'

transmission lever; a bar operatively connected with said mechanism; said transmission lever Y being interposed in the brake rigging and pivoted at an end portion therein; the opposite end portion of said transmission lever being operatively connected to the aforesaid bar; and the said transmission lever intermediate the ends thereof being operatively connected to the said dead lever; the aforesaid mechanism, operating lever, first named means, and the said bar being adapted to impose movement upon the said transmission lever thereby effecting movement of the dead lever and the live cylinder lever to maintain a substantially uniform brake piston travel; and the said uniform brake piston travel regulating the slack within the brake rigging.

14. The combination with a push rod, a live cylinder lever, a dead lever, and an operative connection between said levers as comprised in a brake equipment; an operating mechanism; an

operating lever; means provided whereby said operating lever is oscillated upon movement of the push rod; means carried by said operating lever foroperating the aforesaid mechanism upon abnormal movement of said rod; normal move ment of said rod oscillating said operating lever independently of said mechanism; means for preventing the retrograde movement of said mechanism; a transmission lever; a bar operatively connected with said mechanism; said transmission lever being constructed and arranged whereby an, end portion thereof being operatively connected to said bar, the opposite end portion thereof being interposed and pivoted within the brake rigging, and the central portion thereof being operatively connected to the said dead lever; the said mechanism, operating lever, second named means, and the said bar being adapted for imposing push upon the said transmission lever thereby effecting movement of the dead lever and the live cylinder lever to maintain a substantially uniform brake piston travel; and the said uniform brake piston travel regulating the slack within the brake rigging.

15. A slack adjuster for a brake rigging comprising a rotating member embodied with a rack and pinion and provided with a plurality of circumferentially arranged ratchet teeth; a dead lever comprised in said rigging; a transmission lever; the aforesaid rack, the dead lever, and the transmission lever being combined and arranged whereby the said transmission lever is interposed in the brake rigging, pivoted among the parts thereof, and in itscentral portion operatively connected with the said dead lever; a push rod of the brake equipment; an operating lever connecting said push rod with the rotating member; a pawl carried by said operating lever and engageabl-e with the ratchet teeth; said rotating member having a second series of relatively small teeth extending therearound; a pawl engaging said second teeth for holding the rotating member against retrograde movement; the first named pawl normally co-acting with a single tooth of the first named series but engaging an adjacent tooth following the action of the second named pawl engaging a succeeding number of the second seriesof teeth upon abnormal travel of the push rod; the said second pawl and the second series of teeth being adapted to co-operate with the first named pawl and the first series of teeth whereby the said second pawl successively engages several of the teeth of the said second series between the actions of the first named pawl engaging successively two adjacent teeth of the first named series; the combination herein above set forth. being adapted to operate simultaneously with the brake application; and thereby effect ing a resistance to undesired action substantially as specified.

16. A slack adjuster for a brake rigging comprising a rotating member embodied with a rack and pinion and provided with a plurality of circumferentially arranged elongated ratchet teeth; amember comprised in said rigging; a transmission lever; the aforesaid rack, the member comprised in the rigging, and the transmission lever being combined and arranged whereby the said transmission lever is interposed in the brake rigging, pivoted among the parts thereof, and in its central portion operatively connected with the member comprised in the said rigging; a push rod of the brake equipment; an operating lever operatively connecting said push rod with the rotating member; a pawl carried by said operating lever and engageable with the ratchet teeth; said rotating member having a second series of relatively small teeth extending therearound and arranged in succession one immediately adjacent to the other; a pawl engaging saidsecond teeth for holding the rotating member against retrograde movement; the first named pawl normally co-acting with a single tooth of the first named series but engaging an adjacent tooth following the action of the second named pawl engaging a succeeding number of the second series of teeth upon abnormal travel of the push rod; the combination herein above set forth being adapted to operate simultaneously with the brake application, and thereby effecting a resistance to undesired action substantially as specified.

17. A slack adjuster for a brake rigging comprising a rotating member embodied with a rack and pinion and provided with a plurality of ciroumferentially arranged elongated ratchet teeth; a member comprised in said rigging; a transmission lever; the aforesaid rack, the member comprised in the rigging, and the transmission lever being combined and arranged whereby the said transmission lever is interposed in the brake rigging, pivoted among the parts thereof, and in its central portion operatively connected withthe member comprised in the said rigging; a push rod of the brake equipment; an operating lever operatively connecting said push rod with the rotating member; a pawl carried by said operating lever and engageable with the ratchet teeth; said rotating member having a second series of relatively small teeth extending therearound and arranged in succession one immediately adjacent to the other; said teeth being equi-distantly spaced and with a plurality of said teeth within the perpendicular alignments of the first named teeth; a pawl engaging said second teeth for holding the rotating member against retrograde movement; the first named pawl normally co-acting with a single tooth of the first named series but engaging an adjacent tooth following the action of the second named pawl engaging a succeeding number of the second series of teeth upon abnormal travel of the push rod; the combination herein above set forth being adapted to operate simultaneously with the brake application, and thereby effecting a resistance to undesired action substantially as specified.

18. A slack adjuster having, in combination a push rod and a dead cylinder lever of a brake equipment; an operating mechanism positioned I to the side of .said rod and operatively connected pivoted at the opposite end portion thereof, and in its central portion is operatively connected to the said dead cylinder lever; means operating upon abnormal travel of the aforesaid rod effecting the operation of the said mechanism; the said transmission lever being adapted to transmit the said operation of the mechanism to the aforesaid dead cylinder lever thereby taking slack out of the rigging of the aforesaid equipment and maintaining a substantially uniform brake piston travel.

19. A slack adjuster having, in combination a push rod and a dead cylinder lever of a brake equipment; an operating mechanism; an operative connection between the said mechanism and the aforesaid rod; said connection including an operating lever; normal movement of said rod operating said operating lever independently of the aforesaid mechanism; a transmission lever constructed and arranged whereby an end portion thereof is operatively connected to the said mechanism, pivoted at the opposite end portion thereof, and in its central portion is operatively connected to the dead cylinder lever; means carried by said operating lever to operate the said mechanism upon abnormal travel of the aforesaid rod; means for holding said mechanism against retrograde movement; the said transmission lever being adapted to transmit the operations of the said mechanism to the aforesaid dead cylinder lever thereby taking slack out of the rigging of the said equipment and determining a substantially uniform brake piston travel.

20. A slack adjuster having, in combination a push rod and a dead cylinder lever of a brake equipment; an operating mechanism; an operative connection between said mechanism and the aforesaid rod; said connection including an operating lever and adapted to swing with respect to the axial center of the mechanism; a transmission lever constructed, arranged and combined whereby an end portion thereof is operatively connected to the aforesaid mechanism, pivoted at the opposite end portion thereof, and in its central portion is operatively connected to the said dead cylinder lever; means carried by said operating lever to operate said mechanism upon abnormal travel of the aforesaid rod; means for holding said mechanism against retrograde movement; the said transmission lever being adapted to transmit the operations of the said mechanism to the aforesaid dead cylinder lever whereby a substantially uniform brake piston travel is maintained; and the said uniform brake piston travel regulating the slack within the brake rigging.

21. A slack adjuster having, in combination a push rod and a dead cylinder lever of a brake equipment; an operating mechanism; an operating lever connecting the said mechanism with the aforesaid rod; said operating lever having an end portion operatively connected to the said rod, and the other end portion thereof operatively connected to the aforesaid mechanism; a transmission lever constructed, arranged and combined whereby an end portion thereof is operatively connected to the aforesaid mechanism, pivoted at the opposite end portion thereof, and in its central portion is operatively connected to the said dead cylinder lever; means carried by the said operating lever to operate the said mechanism upon abnormal travel of the aforesaid rod; means for holding said mechanism against retrograde movement; the said transmission lever being adapted to transmit the operations of the said mechanism to the aforesaid dead cylinder lever ating mechanism upon abnormal travel of said push rod, and a single transmission between said operating mechanism and said dead cylinder lever, said transmission including a lever pivoted at its mid-portion to said dead cylinder lever,- said transmission being adapted to transmit the operation of the operating, mechanism to the dead cylinder lever, thereby taking slack out of the brake rigging and maintaining a substantially uniform brake piston travel.

/ JAMES W. CLARK. 

